Low magnetic interference battery

ABSTRACT

A low magnetic interference battery is provided, the battery insertable into a mobile communication device, the mobile communication device comprising a radio interconnected with a microphone and a receiver. The battery comprises a battery portion enabled to provide electrical power to the radio, the battery portion emitting a magnetic field when in operation. The battery further comprises a sealing portion for sealing the battery portion therein such that the battery portion is protected from moisture, the sealing portion comprising a magnetic shield portion arranged relative to the battery portion such that magnetic flux from the battery portion is routed away from the receiver when the battery is in operation in the mobile communication device.

RELATED APPLICATIONS

This patent application is a continuation of U.S. patent applicationSer. No. 12/752,705, filed Apr. 1, 2010, which claims the benefit ofU.S. Provisional Application No. 61/225,364, filed Jul. 14, 2009, bothof the applications are hereby incorporated by reference in theirentirety.

TECHNICAL FIELD

The present disclosure relates generally to batteries and moreparticularly to a battery characterized by low magnetic interference.

BACKGROUND

Mobile communication devices are popular for business and personal use.Such devices include Personal Digital Assistants (PDAs), cellular phonesand smart phones. These devices provide wireless two-way voice and datacommunication over wireless networks such as GSM/GPRS, CDPD, TDMA, iDENMobitex, DataTAC, EDGE or UMTS networks, and broadband networks likeBluetooth and variants of 802.11.

It is desirable that the electromagnetic fields generated by suchdevices be minimized for health reasons and in order to reduceinterference with other nearby electronic devices. For example,international standards on Hearing Aid Compatibility (HAC) establish aminimum signal-to-noise (SNR) ratio at the T-coil of a hearing aid (forexample, see section 7.3.4 “Signal Quality” of ANSI C63.19-2007) foreffective magnetic wireless coupling to the hearing aid (includinghearing aids, cochlear implants, and assistive listening devices) whileminimizing magnetic interference. The hearing aid compatibilityrequirements are generally evaluated with the hearing aid coil in closeproximity to the receiver in the mobile communication device.Traditional approaches to meeting the required signal-to-noise ratio inthe presence of magnetic fields generated by mobile communicationdevices include increasing current in the mobile communication devicereceiver, installing a separate T-coil within the mobile communicationdevice, and altering current loops and circuit board traces within themobile communication device to minimize magnetic interference.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a block diagram illustrating a wireless mobile communicationdevice in accordance with the present disclosure;

FIG. 2 is a perspective view of a conventional battery for powering thewireless mobile communication device of FIG. 1;

FIG. 3A is a schematic representation of positive and negativeelectrodes of a prior art battery such as that shown in FIG. 2, in anun-rolled configuration;

FIG. 3B is a schematic representation of positive and negativeelectrodes of a prior art battery such as that shown in FIG. 2, in arolled-up configuration;

FIG. 4 is a schematic representation of positive and negative contactpads of a prior art battery such as that shown in FIG. 2;

FIG. 5 is a schematic representation of a cross section of a side viewof a prior art battery emitting magnetic flux in operation;

FIG. 6 is a schematic representation of a cross section of a prior artwireless mobile communication device powered by a prior art batterytherein, and further depicting magnetic flux emitted from the battery;

FIG. 7 a is a schematic representation of a cross section of a batteryincorporating a battery portion and a magnetic shield portion;

FIG. 7 b is a schematic representation of a perspective view of abattery incorporating a battery portion and a magnetic shield portion;

FIG. 8 is a schematic representation of a cross section of a wirelessmobile communication device powered by the battery of FIGS. 7 a and b,and further depicting magnetic flux emitted from the battery;

FIG. 9 comprises FIGS. 9 a and 9 b and is a schematic representation ofa cross section of a wireless mobile communication device incorporatinga magnetic shield portion;

FIG. 10 is a schematic representation of a side view of a batteryincorporating a battery portion and a magnetic shield portion, themagnetic shield portion encompassing the battery portion;

FIGS. 11 a and 11 b are schematic representations of a model of acurrent loop representative of a battery in a mobile communicationdevice;

FIGS. 12 a and 12 b are schematic representations of a model of acurrent loop representative of a battery in a mobile communicationdevice with a magnetic shield portion in place;

FIG. 13 is a schematic representation of a cross section of a prior artbattery incorporating structural elements;

FIG. 14 is a schematic representation of a cross section of a batteryincorporating a magnetic shield portion and a structural element, themagnetic shield portion also providing structural support;

FIG. 15 is a schematic representation of a cross section of a batteryincorporating two magnetic shield portions, each magnetic shield portionalso providing structural support;

FIG. 16 comprises a schematic representation of a cross section of aprior art battery, a battery portion of the battery sealed inside asealing portion;

FIG. 17 comprises a schematic representation of a cross-section of abattery, wherein a sealing portion comprises a magnetic shield portion;

FIG. 18 comprises a schematic representation of a cross-section of abattery, wherein a sealing portion comprises a magnetic shield portion;

FIG. 19 comprises a schematic representation of a cross section of aprior art battery, a battery portion of the battery sealed inside a softsealing case;

FIG. 20 comprises a schematic representation of a cross-section of aprior art soft sealing case;

FIG. 21 comprises a schematic representation of a cross-section of abattery, a battery portion of the battery sealed inside a soft sealingcase incorporating a magnetic shield portion;

FIG. 22 comprises a schematic representation of a cross section of thesoft sealing case of FIG. 21, according to non-limiting embodiments; and

FIG. 23 comprises a schematic representation of a cross section of thesoft sealing case of FIG. 21, according to non-limiting embodiments.

DETAILED DESCRIPTION

Magnetic noise may be generated by a battery of a mobile communicationdevice due to current draw associated with GSM radio transmission.Accordingly, it is desirable to minimize magnetic interference frommobile communication devices in general and to minimize magneticinterference from mobile communication device batteries due to currentdraw on the battery.

An aspect of the specification provides a battery, insertable into amobile communication device, the mobile communication device comprisinga radio interconnected with a microphone and a receiver. The batterycomprises a battery portion enabled to provide electrical power to theradio, the battery portion emitting a magnetic field when in operation.The battery further comprises a sealing portion for sealing the batteryportion therein such that the battery portion is protected frommoisture, the sealing portion comprising a magnetic shield portionarranged relative to the battery portion such that magnetic flux fromthe battery portion is routed away from the receiver when the battery isin operation in the mobile communication device.

The sealing portion can comprise a rigid sealing can, providingstructural stability to the battery. At least a portion of the sealingcan comprise a high magnetic permeability material such that themagnetic shield portion is structurally incorporated into the sealingcan. The sealing can comprise a can portion, for containing the batteryportion therein, and a plate portion, attached to the can portion, forsealing the battery portion in the sealing can.

The magnetic shield portion can comprise a coating on the sealingportion.

The sealing portion can comprise a soft sealing case. The soft sealingcase can comprise at least one flexible layer of insulating material andat least one flexible layer of high magnetic permeability material, suchthat the magnetic shield portion is integrated into the soft sealingcase via the at least one flexible layer of high magnetic permeabilitymaterial, the soft sealing case further comprising a layer of theinsulating material on a battery portion side of the soft sealing case.The soft sealing case can further comprise at least one flexible layerof metal foil.

The magnetic shield portion can comprise Mu Metal.

The battery can further comprise connectors to the battery portionthrough the sealing portion.

A discussion of the prior art and exemplary embodiments follow hereafterwith reference to the drawings.

FIG. 1 is a block diagram illustrating some of the components of awireless mobile communication device 130. In the embodiment depicted inFIG. 1, wireless mobile communication device 130 includes acommunication subsystem 200 for wireless two-way data and voicecommunication with the wireless network 120. Communication subsystem 200may include one or more receivers, transmitters, antennas, signalprocessors and other components associated with wireless communicationsincluding but not limited to a radio 201. The particular design of thecommunication subsystem 200 can depend on the network in which thewireless mobile communication device 130 is intended to operate. Theconcepts herein may be applicable to a variety of wireless mobilecommunication devices, such as two-way pagers, cellular telephones, etc.

In the embodiment shown in FIG. 1, network access is associated with asubscriber or user of the wireless mobile communication device 130 via amemory module 202, which may be a Subscriber Identity Module (SIM) cardfor use in a GSM network or a Universal Subscriber Identity Module(USIM) card for use in a Universal Mobile Telecommunication System(UMTS). The SIM card is inserted in or connected to an interface 204 ofthe wireless mobile communication device 130 to operate in conjunctionwith the wireless network 120. Alternatively, the wireless mobilecommunication device 130 may have an integrated identity module for usewith systems such as Code Division Multiple Access (CDMA) systems.

The wireless mobile communication device 130 also includes a batteryinterface 206 for receiving at least one rechargeable battery 208. Thebattery 208 provides electrical power to at least some of the electricalcircuitry in the wireless mobile communication device 130, and thebattery interface 206 provides a mechanical and electrical connectionfor the battery 208. As discussed above and in greater detail below, ithas been discovered that when the mobile communication device 130 isheld in close proximity to a hearing aid device (as is the case duringnormal cell phone usage, for example when a receiver 224 is held closeto a hearing aid device) the time waveform (and frequency spectrum) ofthe Radio Frequency (RF) amplifier current within communicationsubsystem 200 is largely the same as that of the measured magnetic noiseat the hearing aid coil. This indicates that interference problems withthe hearing aid result from magnetic noise generated by currents withinthe communication system associated with GSM radio transmission. Throughsubsequent measurements and analysis, it was found that a large portionof this magnetic noise was generated by the battery, though magneticnoise can be generated by other components of the communication device130.

The communication device 130 also generally includes radio 201 (e.g.within the communication subsystem 200), a microphone 226 and thereceiver 228. The receiver 228 can include, but is not limited to, avoice coil, a hearing aid coil and a separate T-coil.

The wireless mobile communication device 130 may include one or morecircuit boards (not shown) that implement the components describedabove. This disclosure is not limited to any particular electroniccomponent or software module or any combination thereof.

FIG. 2 shows a conventional battery 208 for powering a mobilecommunication device 130. The battery is assembled inside a case 240 andincludes a positive contact pad 250, a negative contact pad 260, and mayinclude a temperature contact pad 270 and a cryptography contact pad 280for testing manufacturer's authenticity of the battery 208. Although notshown, the battery may include an internal microprocessor and a switchin series with the contact pads 250 and 260 which is opened by theinternal microprocessor if the battery discharges below a predeterminedlevel, in order to avoid damage to the battery. Likewise, if the batterytemperature elevates beyond a predetermined level, as indicated on thetemperature contact pad 270, the microprocessor may cause the switch toopen.

A sandwich electrode assembly is located within the case 240, comprisingcoated metallic films that according to the most common configurationsare either stacked, folded back and forth like an accordion (referred toas a Z-type electrode assembly), or rolled up and flattened (referred toas a “jellyroll” electrode assembly). Reference will be made hereinafterto the construction and design of “jellyroll” electrode assemblies,although a person of skill in the art will appreciate that theprinciples set forth herein apply equally to other designs andconfigurations of electrode assemblies.

One such “jellyroll” electrode assembly 300 is schematically representedin FIG. 3A in its un-rolled state and in FIG. 3B in its final rolled-upstate. The exemplary prior art electrode assembly 300 comprises apositive electrode sheet 310 (cathode) and a negative electrode sheet320 (anode) sandwiched together with a separator sheet 330 between them,and a further outer separator sheet 340 that may curl around the end ofthe positive electrode sheet 310 at the innermost section of thejellyroll so as to completely isolate the positive and negativeelectrodes. The separator sheet 330 contains an electrolyte, such aslithium salts, such as LiPF6, LiBF4, or LiClO4, in an organic solvent,such as ether. The electrolyte may also be acid such as in a lead-acidbattery, alkaline electrolyte usually potassium hydroxide in a nickelmetal hydride or nickel cadmium. The positive electrode sheet 310 maycomprise a thin sheet of aluminum (e.g. 15 μm) that is coated on bothsides (e.g. 60-70 μm per side) with Lithium cobalt oxide (LiCoO2), orother suitable material, while the negative electrode sheet 320 maycomprise a thin sheet of copper foil (e.g. 10 μm) that is coated on bothsides with graphite (e.g. 60-70 μm per side), such that electricalcurrent flows from the cathode to the anode. The separator sheet 330(e.g. 20 μm) has openings in it that allow the electrolyte liquid topermeate between the positive and negative electrode sheets 310 and 320.The separator sheet 330 thus physically separates the two electrodesheets while allowing ions to flow between them. Additional details ofthe construction of a conventional jellyroll electrode assembly may befound in the prior art, as exemplified by U.S. Pat. No. 7,488,553(Tsukamoto et al).

Electrical connection between the negative electrode sheet 320 andbattery contact pad 260 may be made via a conducting tab 362 thatextends to an insulated feed-through (for example, as discussed belowand shown schematically in FIG. 6) which connects to a conductive strip360 that is insulated from the case by an insulator 370 and whichextends from the feed-through to the battery contact pad 260, as shownin FIG. 4. Electrical connection between the positive electrode sheet310 and battery contact pad 250 may be made either by leaving thealuminum electrode uncoated in its last roll of the jellyroll structureso as to expose the bare aluminum electrode and spot-welding, orcrimping the last roll of the electrode 310 to the conductive case 240,or by spot-welding or crimping a conducting tab 352 to the case 240,thereby forming an external connection to the positive electrode throughthe case. A further conductive strip 350 may be spot-welded to anopposite side of the case from the spot-welded tab 352, or last roll ofpositive electrode sheet, which extends from the spot-weld on the case240 to the battery contact pad 250, as shown in FIG. 4. In such anarrangement, the positive connection to outside of the case 240 is madeon the opposite side of the battery case to the negative connection, asshown in FIG. 3B. However, it is also known in the art for the positiveand negative connections to outside of the case 240 to be on the sameside.

Power is typically provided from the battery 208 to a device, such ascommunication device 130, via conducting pads (260, 250), as discussedabove. As shown in FIG. 4, a strip of conductor 350 carries the currentfrom the conductive case 240 to the positive pad 250. The connectionfrom the negative feed-through to conductive strip 360 is made on theopposite side of the battery from the positive connection. Theconductive strip 360 carries the current from the feed-through to thenegative pad 260. It will be appreciated that the arrangement of FIG. 4results in large currents flowing externally of the battery case 240.

As shown in FIGS. 3A and 3B, if the connections 352 and 362 to theelectrodes are made at opposite ends of the electrode assembly 300,i.e., one connection is made on the center of the jellyroll and theother on the outside of the jellyroll, current flow within the positiveand negative electrode sheets 310 and 320 is in the same direction.Moreover, the magnitude of the electrode current increases from zero atthe end opposite the connection to maximum at the end with theconnection. Therefore, the magnitude of the current in the twoelectrodes as a function of position is significantly different.

Sources of magnetic noise in the prior art battery design of FIGS. 3 and4 include noise from the electric currents flowing in the jellyrollelectrode assembly 300 and ion current in the electrolyte liquid, theconnections from the electrodes 310, 320 to the feed-throughs, currentsflowing in the battery case 240 and the external conductive strips 350,360.

FIG. 5 depicts a cross-section of a battery 508, similar to battery 208,comprising a case 540 containing a battery portion 509, which in someembodiments is similar to the “jellyroll” described above with referenceto FIG. 3 b. FIG. 5 further depicts the magnetic flux 510 emitted fromthe battery 508 when it is in operation (for example when inserted intothe battery interface 206 of communication device 130, as depicted inFIG. 6). It is understood that the battery portion 509 is the source ofthe magnetic flux 510. Indeed, FIG. 6 depicts the battery 508 insertedinto the battery interface 206, with magnetic flux 510 passing through,and in the general area of, the receiver 224, such that when thereceiver 224 is held adjacent to a hearing aid, the magnetic flux 510will interfere with the operation of the hearing aid by decreasing theSNR of the hearing aid (e.g. noise will increase).

It is furthermore understood that depictions of magnetic flux in FIG. 5,as well as in FIGS. 6, 7 a, 8, 10, 13, 14, 15, 16, 17, 18, 19 and 21 areapproximations. Modeling of magnetic flux from a battery is provided inFIGS. 11 a and 11 b, described below. Modeling of magnetic field from abattery with magnetic shield in place is provided in FIGS. 12 a and 12b, described below.

As described in detail below, magnetic noise may be significantlyreduced (e.g. >10 dB reduction over the prior art) by providing amagnetic shield to direct the magnetic flux 510 away from the region ofthe receiver 224. In some embodiments, as depicted in a schematiccross-section in FIG. 7 a, a battery 708 is provided which comprises abattery portion 710, similar to battery 508 with like elements havinglike numbers, though starting with “7” rather than “5” (e.g. case 740 issimilar to case 540), and a magnetic shield portion 712. The magneticshield portion 712 generally comprises a high magnetic permeabilitymaterial, including but not limited to Mu Metal, however other materialsof suitable magnetic permeability are within the scope of presentembodiments. Furthermore, the magnetic shield portion 712 is arrangedrelative to battery portion 710 so that the magnetic flux 510′ isgenerally routed through the magnetic shield portion 712 such that whenthe battery 708 is inserted into the battery interface 206 of thecommunication device 130, and the battery 708 is in operation, themagnetic flux 510′ is generally routed away from the receiver 224.Hence, in general, at least some portion of magnetic shield portion 712is oriented such that a normal 713 of the magnetic shield portion 712 isgenerally aligned in the direction of the receiver 224 when the battery708 is inserted into the battery interface 206.

It is understood that while in FIG. 7 the magnetic shield portion 712 isexternal to outside to the case 740, in other embodiments the magneticshield portion 712 can be internal to the case 740 (e.g. located betweenthe battery portion 710 and the case 740), for example see FIGS. 14 and15.

The thickness and geometry of the magnetic shield portion 712 can bedependent on the geometry of the magnetic flux 510′, and the position ofthe receiver 224 relative to the battery 708 when inserted into thebattery interface 206. Indeed, the thickness and geometry of themagnetic shield portion 712 can be optimized using the equations ofmagnetostatics:

$\begin{matrix}{{\overset{\rightharpoonup}{\nabla}{\cdot \overset{\rightharpoonup}{B}}} = {{0\mspace{14mu}{and}\mspace{14mu}{\overset{\rightharpoonup}{\nabla}{\times \overset{\rightharpoonup}{H}}}} = {{\frac{4\pi}{c}\overset{\rightharpoonup}{J}\mspace{14mu}{where}\mspace{14mu}\overset{\rightharpoonup}{B}} = {\mu\;\overset{\rightharpoonup}{H}}}}} & \left( {{Equation}\mspace{14mu}{Set}\mspace{14mu} 1} \right)\end{matrix}$whereby B is magnetic flux density, H is magnetic field intensity, c isthe speed of light, j is current density and μ is magnetic permeability.Equation Set 1 is then generally solved with the boundary conditions:

$\begin{matrix}{{{\overset{\rightharpoonup}{B}}_{2} \cdot \overset{\rightharpoonup}{n}} = {{{{\overset{\rightharpoonup}{B}}_{1} \cdot \overset{\rightharpoonup}{n}}\mspace{14mu}{and}\mspace{14mu}{\overset{\rightharpoonup}{B}}_{2} \times \overset{\rightharpoonup}{n}} = {\frac{\mu_{2}}{\mu_{1}}{\overset{\rightharpoonup}{B}}_{1} \times \overset{\rightharpoonup}{n}}}} & \left( {{Equation}\mspace{14mu}{Set}\mspace{14mu} 2} \right)\end{matrix}$whereby B₁ and B₂ are the magnetic flux density in, respectively, afirst medium 1 and an adjacent second medium 2 (e.g. medium 1 comprisesthe medium outside the magnetic shield portion 712 and medium 2comprises the material of the magnetic shield portion 712, such as Mumetal); n is the normal of the interface between medium 1 and medium 2;and μ₁ and μ₂ are the magnetic permeabilities of medium 1 and medium 2,respectively. These equations can be solved using any suitable software,including commercially available software.

FIG. 7 b depicts a perspective view of block diagram battery 708,including the battery portion 710 and the magnetic shield portion 712.For clarity, the case 740 is not depicted in FIG. 7 b, though it isunderstood that magnetic shield portion 712 can be either internal orexternal to the case 740. While in FIGS. 7 a and 7 b, the magneticshield portion 712 is depicted as having the same general area of thebattery portion 710, it is understood that the magnetic shield portion712 can be smaller or larger than the area of the battery portion 710,as desired, as long as there is an overall reduction in magnetic flux inthe area of the receiver 224 when the battery 708 is in operation in thecommunications device 130 (see FIG. 8 below). Furthermore, while inFIGS. 7 a and 7 b, magnetic shield portion 712 is depicted as beingincorporated on a face of the battery portion 710 and/or the case 740,this is not to be considered particularly limiting; indeed, as describedabove, the magnetic shield portion 712 can be located internal orexternal to the case 740.

Turning now to FIG. 8, when battery 708 is inserted in battery interface206 of communication device 130, the magnetic flux 510′ is directed awayfrom the general area of the receiver 224, hence reducing interferencewith a hearing aid adjacent to receiver. Hence, it is understood thatmagnetic shield portion 712 is arranged on a side of the battery portion710 which, when inserted into communication device 130, is generallyfacing the receiver.

In alternative non-limiting embodiments, as depicted in FIG. 9 a, amagnetic shield portion 912, similar to magnetic shield portion 712, isincorporated into communication device 130. The magnetic shield portion912 is generally located between the battery interface 206 and thereceiver such that at least one normal of the magnetic shield portion912 is pointing in a direction of a magnetic field emitted from abattery (not depicted) inserted into battery interface 206 when thebattery is in operation in the communication device 130. Hence, magneticflux will be conducted away from the receiver 224 when the battery is inoperation, as in FIG. 7.

While in FIG. 9 the magnetic shield portion 912 is depicted as havingthe same general area of battery interface 206, it is understood thatthe area of the magnetic shield portion 912 can be smaller or largerthan the area of the battery interface 206, as desired, as long as thereis an overall reduction in magnetic flux in the area of the receiver224. Furthermore, while in FIG. 9, magnetic shield portion 912 isdepicted as being incorporated into battery interface 206, this is notto be considered particularly limiting; indeed, the magnetic shieldportion 912 can be located in any suitable part of communication device130, between the battery interface 206 and receiver. For example, asdepicted in FIG. 9 b, a magnetic shield portion 912′ can be incorporatedinto the body of the communication device 130.

It is further understood that embodiments such as that depicted in FIG.9 b shield the area of the receiver 224 not only from magnetic fluxemitted from a battery inserted into the battery interface 206, but fromother sources of magnetic interference within the communication device130.

Attention is now directed to FIG. 10, which depicts alternativenon-limiting embodiments of a battery 1008, similar to battery 708, withlike elements having like numbers, however starting with “10” ratherthan “7”. However, in these embodiments, the magnetic shield portion1012 comprises a plurality of interconnected planes 1090 a, 1090 b, 1090c, 1090 d, each having a respective normal 1013 a, 1013 b, 1013 c, 1013d, such that the battery portion 1010 is generally encompassed by themagnetic shield portion 1012. While only four of the interconnectedplanes are depicted in FIG. 10, it is understood that each side of thebattery portion 1010 is associated with a respective plane of themagnetic shield portion 1012. In other words, if the battery portion1010 is generally a rectangular box, then the magnetic shield portion1012 is also a generally rectangular box of proportions similar to thebattery portion 1010, however with apertures there through forelectrodes 1050, 1060, 1070 and 1080. Hence, magnetic flux 510″ emittedfrom the battery portion 1010 when in operation, is now largelycontained within the magnetic shield portion 1012.

Attention is now directed to FIGS. 11 a and 11 b, which depict magneticfield lines of a model of a current loop 1110 of radius 0.05, accordingto non-limiting embodiments. FIG. 11 b is similar to FIG. 11 a, butdepicts only the right hand side of FIG. 11 a. It is understood thateach of FIGS. 11 a and 11 b have been modeled with arbitrary units. Itis furthermore understood that the current loop depicted in FIGS. 11 aand 11 b can be used to model the battery 508.

Attention is now directed to FIGS. 12 a and 12 b, which are similar toFIGS. 11 a and 11 b, respectively, however each of the models depictedin FIGS. 12 a and 12 b include a magnetic shield portion 1212 a and 1212b, respectively, each similar to magnetic shield portions 712, 912, 1012described above. Furthermore, the magnetic permeability of the magneticshield portion 1212 b being greater than the magnetic permeability ofthe magnetic shield portion 1212 a. In any event, from a comparison ofFIGS. 11 a and 11 b, it is understood that there is a reduction inmagnetic flux to the right of the magnetic shield portion 1212 a. FIGS.11 a and 12 a are understood to represent a communication device, withthe current loop 1110 representative of a battery in the communicationdevice, and the magnetic shield portion 1212 a representative of amagnetic shield portion in the communication device. FIG. 11 arepresents the communication device without a magnetic shield portionand FIG. 12 a represents the communication device with a magnetic shieldportion. Hence, from a comparison of FIGS. 11 a and 12 a, it isunderstood that a receiver of the communication device located to theright of the magnetic shield portion 1212 a would experience a reductionin magnetic flux with the magnetic shield portion when compared to acommunication device without the magnetic shield portion 1212 a.Similarly, it is understood that a similar reduction in magnetic flux ispresent between FIGS. 11 b and 12 b; furthermore, from a comparison ofFIGS. 12 a and 12 b, it is understood that by increasing magneticpermeability of a magnetic shield portion, the magnetic flux can befurther reduced (i.e. the magnetic flux to the right of the magneticshield portion 1212 b is less than the magnetic flux to the right of themagnetic shield portion 1212 a).

Attention is now directed to FIG. 13, which depicts a battery 1308,similar to the battery 508 depicted in FIG. 5, with like elements havinglike numbers, however preceded by a “13” rather than a “5”. For example,the battery 1308 comprises a case 1340 similar to the case 540. However,the battery 1308 further comprises structural elements 1350 a and 1350b. For example, in some embodiments, the case 1340 can be comprisedprimarily of plastic. Hence to give the battery 1308 structuralstability, for example to meet ruggedness testing, the structuralelements 1350 a, 1350 b can comprise plates made from any suitablemetal, such as stainless steel and aluminum, and are of a suitablethickness to provide structural stability to the battery 1308. Ingeneral, each structural element 1350 a and 1350 b can be the same ordifferent thicknesses, as desired. It is understood that the structuralelements 1350 a, 1350 b generally sandwich the battery portion 1309inside the case 1340. FIG. 13 further depicts magnetic flux 1310,similar to the magnetic flux 510, emitted from the battery portion 1309,when the battery 1308 is in operation. Similar to the description of thebattery 508 described above, the magnetic flux 1310 from the battery1308 can interfere with operation of a hearing aid, by decreasing theSNR of the hearing aid (e.g. noise will increase), when the battery 1308is in operation in the mobile communication device 130, and the receiver224 is held adjacent to the hearing aid.

Attention is now directed to FIG. 14, which depicts a battery 1408,similar to the battery 1308, with like elements having like numbers,however preceded by a “14” rather than a “13”. For example, the battery1408 comprises a case 1440 similar to the case 1340. However the battery1408 includes a first structural element 1450, similar to the structuralelement 1350 a, and a magnetic shield portion 1412. Magnetic shieldportion 1412 is similar to structural element 1350 b, however magneticshield portion 1412 generally comprises a high magnetic permeabilitymaterial, similar to the magnetic shield portion 712. The high magneticpermeability material can include, but is not limited to, Mu Metal, andit is understood that other materials of suitable magnetic permeabilityare within the scope of present embodiments. Furthermore, the magneticshield portion 1412 is on a side of the battery portion 1409 such thatthe magnetic flux 1410 is generally routed through the magnetic shieldportion 1412 such that when the battery 1408 is inserted into thebattery interface 206 of the communication device 130. In other words,when the battery 1408 is in operation, the magnetic flux 1410 isgenerally routed away from the receiver 224, similar to the battery 708.

Furthermore, the magnetic shield portion 1412 provides structuralstability to the battery 1408, similar to the structural element 1350 b,and hence the magnetic shield portion 1412 can comprise a plate madefrom any suitable high magnetic permeability metal, such as Mu Metal,and is of a suitable thickness to provide structural stability to thebattery 1408. It is hence understood that the structural element 1450and the magnetic shield portion 1412, generally sandwich the batteryportion 1409 inside the case 1440. Hence, in general, structural element1450 and the magnetic shield portion 1412 provide similar structuralfunctionality to the battery 1408 as the structural element 1350 a and1350 b in the battery 1308, however the magnetic shield portion 1412further routes the magnetic flux away from the receiver 224 when thebattery 1408 is in operation in the mobile communication device 130. Ingeneral, it is further understood that each of the magnetic shieldportion 1412 and structural element 1450 can be the same or differentthicknesses, as desired.

Attention is now directed to FIG. 15, which depicts a battery 1508,similar to the battery 1408, with like elements having like numbers,however preceded by a “15” rather than a “14”. For example, the battery1508 comprises a case 1540 similar to the case 1440. However the battery1508 includes a first magnetic shield portion 1512 a, similar to themagnetic shield portion 1412, and a second magnetic shield portion 1512b, similar to magnetic shield portion 1412. Magnetic shield portions1512 a and 1512 b are similar to structural elements 1350 a and 1350 b,respectively, each of magnetic shield portions 1512 a and 1512 bgenerally comprises a high magnetic permeability material, similar tothe magnetic shield portion 712. The high magnetic permeability materialcan include, but is not limited to, Mu Metal, and it is understood thatother materials of suitable magnetic permeability are within the scopeof present embodiments. Furthermore, the magnetic shield portions 1512 ais on a side of the battery portion 1509 such that the magnetic flux1510 is generally routed through the magnetic shield portion 1512 a suchthat when the battery 1508 is inserted into the battery interface 206 ofthe communication device 140. In other words, when the battery 1508 isin operation, the magnetic flux 1510 is generally routed away from thereceiver 224, similar to the battery 708. However, as the magneticshield portion 1512 b also comprises a high magnetic permeabilitymaterial, the magnetic flux 1510 is also routed through the magneticshield portion 1512 b. In general, as magnetic shield portions 1512 aand 1512 b sandwich the battery portion 1509, a significant portion ofthe magnetic flux 1510 is generally contained within the battery 1508.

Furthermore, each of the magnetic shield portions 1512 a and 1512 bprovides structural stability to the battery 1508, similar to thestructural elements 1350 a and 1350 b, and hence each of the magneticshield portions 1512 a and 1512 b can comprise a plate made from anysuitable high magnetic permeability metal, such as Mu Metal, and areeach of a suitable thickness to provide structural stability to thebattery 1508. In general, it is further understood that each of themagnetic shield portions 1512 a and 1512 b can be the same or differentthicknesses, as desired. As it is further understood that the magneticshield portions 1512 a and 1512 b generally sandwich the battery portion1509 inside the case 1540, the magnetic shield portions 1512 a and 1512b provide similar structural functionality to the battery 1508 as thestructural element 1350 a and 1350 b in the battery 1308, however themagnetic shield portions 1512 a and 1512 b further route the magneticflux away from the receiver 224 when the battery 1508 is in operation inthe mobile communication device 140.

Attention is now directed to FIG. 16, which depicts a cross-section of abattery 1608, similar to battery 508 of FIG. 5, with like elementshaving like numbers, however preceded by “16” rather than “5”. Forexample, the battery 1608 comprises a case 1640 similar to case 540. Ingeneral, the case 1640 contains a battery portion 1609, which in someembodiments is similar to the “jellyroll” described above with referenceto FIG. 3 b. Further, the battery portion 1609 is sealed inside asealing can 1645. The sealing can 1645 comprises a can portion 1646 anda sealing plate portion 1647, the sealing plate portion 1647 sealed tothe can portion 1646 such that the battery cell 1609 is sealed insidethe sealing can 1645 within case 1640. The sealing plate portion 1647can be sealed to the can portion 1646 using any suitable method,including but not limited to welding and glue. Furthermore, the at leastone of the can portion 1646 and the plate portion 1647 can compriseapertures and/or electrical connectors for making electrical connectionto the battery portion 1609. The sealing can 1645 can comprise anysuitable metal, including but not limited to aluminum, and further canbe of any suitable thickness. The sealing can 1645 can further comprisesuitable apertures (not depicted) for tabs of the battery portion 1609,similar to tabs 352, 362 of FIG. 3B, such that electrical contact can bemade to the battery portion 1609. It is understood that the sealing can1645 protects the battery cell 1609 against moisture, and can furtherprovide structural support for the battery 1608.

FIG. 16 further depicts the magnetic flux 1610 emitted from the battery1608 when it is in operation (for example when inserted into the batteryinterface 206 of communication device 130, similar to the battery 508and communication device 130 as depicted in FIG. 6). It is understoodthat the battery portion 1609 is the source of the magnetic flux 1610.As in FIG. 6 when the battery 1608 is inserted into the batteryinterface 206, the magnetic flux 1610 passes through, and in the generalarea of, the receiver 224, such that when the receiver 224 is heldadjacent to a hearing aid, the magnetic flux 1610 will interfere withthe operation of the hearing aid by decreasing the SNR of the hearingaid (e.g. noise will increase).

Attention is now directed to FIG. 17, which depicts a schematiccross-section of a battery 1708, similar to battery 1608 of FIG. 16,with like elements having like numbers, however preceded by “17” ratherthan “16”. For example, the battery 1708 comprises a sealing can 1745similar to sealing can 1645, however sealing can 1745 comprises amagnetic shield portion 1712, which has a similar functionality to themagnetic shield portion 712, in that the magnetic flux 1710 from thebattery portion 1709 is routed through the magnetic shield portion 1712in order to route the magnetic flux 1710 away from the receiver 224 whenthe battery 1708 is in operation in communications device 130. In thedepicted embodiment, the magnetic shield portion is located on a face ofthe sealing can 1745 which faces a receiver side of the communicationsdevice 130 when the battery 1708 is inserted into communications device130.

In some embodiments, the magnetic shield portion 1712 can comprise aplate of a suitable high magnetic permeability material, including butnot limited to Mu Metal, attached to a face of the sealing can 1745. Inother embodiments, the magnetic shield portion 1712 can comprise acoating of a suitable high magnetic permeability material, using anysuitable coating technique, including but not limited to platingtechniques, spray coating methods, heating adhesion coating methods,chemical deposition methods, and the like. In some embodiments, otherportions of the sealing can 1745 can be coated with high magneticpermeability material, including both the can portion 1746 and thesealing plate portion 1747. In some embodiments, the entire sealing can1745 can be substantially coated with a high magnetic permeabilitymaterial, such that magnetic flux is largely contained within thebattery 1708, for example see FIG. 18.

Attention is now directed to FIG. 18, which depicts a schematiccross-section of a battery 1808, similar to battery 1708 of FIG. 17,with like elements having like numbers, however preceded by “18” ratherthan “17”. For example, the battery 1808 comprises a sealing can 1845similar to sealing can 1745, however the sealing can 1845 comprises ahigh magnetic permeability material, including but not limited to MuMetal. In other words, the sealing can 1845 is manufactured from MuMetal (and the like), rather than aluminum or stainless steel. Hence, inaddition to sealing the battery portion 1809, and providing structuralstability for the battery 1809, the sealing can 1845 also functions as amagnetic shield, similar to magnetic shield 1012 depicted in FIG. 10,however, located inside case 1840 and further providing structuralsupport and battery portion sealing functionality.

While in the embodiment depicted in FIG. 18, both the can portion 1846and the sealing plate portion 1847 comprise a high magnetic permeabilitymaterial, in yet further embodiments, one of the can portion 1846 andthe sealing plate portion 1847 can comprise a high magnetic permeabilitymaterial, while the other of the can portion 1846 and the sealing plateportion 1847 comprises another material, such as aluminum, stainlesssteel, and the like. In each of these embodiments, the element (i.e. oneof the can portion 1846 and the sealing plate portion 1847) thatcomprises the high magnetic permeability material routes the magneticflux away 1810 from the receiver 224 when the battery 1808 is inoperation in communication device 130.

Attention is now directed to FIG. 19, which depicts a schematiccross-section of a battery 1908, similar to battery 1608 of FIG. 16,with like elements having like numbers, however preceded by “19” ratherthan “16”. For example, the battery 1908 comprises a soft sealing case1945, the battery portion 1909 sealed inside the soft sealing case 1945.FIG. 20 depicts a schematic cross-section of the soft sealing case 1945:the soft sealing case 1945 can comprise layers of flexible insulatingmaterial 2010 and flexible foil 2020. The insulating material 2010 cancomprise any suitable insulating material, including but not limited topolymers, of any suitable thickness; the foil 2020 can be of anysuitable metal, including but not limited to aluminum, of any suitablethickness. Furthermore, the soft sealing case 1945 can comprise anysuitable number of layers of insulating material 2010 and foil 2020, inany suitable order, such that the soft sealing case 1945 protects thebattery portion 1909 from moisture. For example, while in FIG. 20, thesoft sealing case 1945 is depicted as having 7 layers, in otherembodiments, the soft sealing case 1945 can comprise three layers: alayer of foil 2020 sandwiched between two insulating layers 2010. In anyevent, it is understood that an insulating layer 2010 is on a batteryportion side of the soft sealing case 1945 (i.e. inside) such thatelectrical properties of the soft sealing case 1945 do not interferewith the battery portion 1909.

In some embodiments, the soft sealing case 1945 comprises a flexiblepouch, with at least one side deformed to provide space for the batteryportion 1909. The flexible pouch can comprise two sheets of suitablematerial, which are heat sealed together with the battery portion 1909therein. Furthermore, it is understood that tabs of the battery portion1909, similar to tabs 352 and 362 depicted in FIG. 3B, can extendthrough the soft sealing case 1945 such that electrical connection canbe made with the battery portion 1909.

Attention is now directed to FIG. 21, which depicts a schematiccross-section of a battery 2108, similar to battery 1908 of FIG. 19,with like elements having like numbers, however preceded by “21” ratherthan “19”. For example, the battery 2108 comprises a soft sealing case2145 similar to soft sealing case 1945, however the soft sealing case2145 comprises a high magnetic permeability material, including but notlimited to Mu Metal. For example, in some embodiments, the soft sealingcase 2145 can be coated with the high magnetic permeability materialusing any suitable coating technique, including but not limited to spraycoating methods, heat adhesion coating methods, chemical depositionmethods, and the like. In some of the embodiments, the individual sheetsof the soft sealing case 2145 can be coated with the high magneticpermeability material prior to being heat sealed together and/ordeformed.

In other embodiments, the high magnetic permeability material can beincorporated into the soft sealing case 2145 by replacing the aluminumfoil (and the like) with foil comprising the high magnetic permeabilitymaterial. For example, FIG. 22 depicts a schematic cross-section of anon-limiting embodiment of the soft sealing case 2145 comprising aflexible layer 2220 of a high magnetic permeability material, includingbut not limited to Mu Metal foil, sandwiched between two flexible layers2210 of an insulating material, including but not limited to a polymermaterial. In these embodiments, the thickness of the layer 2220 can beoptimized to balance strength, magnetic shield and flexibility.Furthermore, it is understood that the soft sealing case 2145 cancomprise any suitable number of layers of foil 2220 and any suitablenumber of layers 2210 of insulating material, in any suitable order,though generally the battery portion side of the soft sealing case 2145comprises a layer 2210 of the insulating material, as described above.

In some embodiments, as depicted in schematic cross-section in FIG. 23,the soft sealing case 2145 can comprise at least one layer 2320 offlexible metal foil, including but not limited to aluminum foil, inaddition to at least one layer 2220 of high magnetic permeabilitymaterial and at least one layer 2210 of insulating material.Incorporation of the at least one layer 2320 of metal foil can improvecertain physical properties of the soft dealing case 2145, such asstrength.

Persons skilled in the art will appreciate that there are yet morealternative implementations and modifications possible for implementingthe embodiments, and that the above implementations and examples areonly illustrations of one or more embodiments. The scope, therefore, isonly to be limited by the claims appended hereto.

What is claimed is:
 1. A power pack comprising: a battery portionproducing magnetic flux when in operation; and, a sealing portionconfigured to seal the battery portion therein such that the batteryportion is protected from moisture, the sealing portion comprising amagnetic shield portion configured to prevent the magnetic flux fromleaking through a receiver side of the power pack.
 2. The power pack ofclaim 1, wherein the magnetic shield portion is internal to the sealingportion.
 3. The power pack of claim 1, wherein the magnetic shieldportion comprises a coating on a surface of the sealing portion.
 4. Thepower pack of claim 1, wherein the sealing portion comprises a rigidsealing can, providing structural stability to the battery.
 5. The powerpack of claim 4, wherein the magnetic shield portion is structurallyincorporated into the rigid sealing can.
 6. The power pack of claim 5,wherein the magnetic shield portion comprises a high magneticpermeability material.
 7. The power pack of claim 4, wherein the rigidsealing can comprises a can portion configured to contain the batteryportion therein, and a plate portion, attached to the can portion,configured to seal the battery portion in the sealing can.
 8. The powerpack of claim 1, wherein the sealing portion comprises a soft sealingcase.
 9. The power pack of claim 8, wherein the soft sealing casecomprises at least one flexible layer of insulating material and atleast one flexible layer of high magnetic permeability material.
 10. Thepower pack of claim 9, wherein the magnetic shield portion comprises theat least one flexible layer of high magnetic permeability material. 11.The power pack of claim 9, wherein the soft sealing case furthercomprises a layer of the flexible insulating material on a batteryportion side of the soft sealing case.
 12. The power pack of claim 9,wherein the soft sealing case further comprises at least one flexiblelayer of metal foil.
 13. The power pack of claim 1, wherein the magneticshield portion is further configured to substantially contain themagnetic flux within the sealing portion.
 14. The power pack of claim 1,wherein the magnetic shield portion is further configured to route themagnetic flux there through.
 15. The power pack of claim 1, wherein themagnetic shield portion is further configured to prevent the magneticflux from leaking through a receiver side portion of the power pack. 16.The power pack of claim 1, wherein the magnetic shield portion comprisesa high magnetic permeability material.
 17. The power pack of claim 1,wherein the magnetic shield portion comprises Mu Metal.
 18. The powerpack of claim 1, further comprising connectors to the battery portionthrough the sealing portion.